If you have WebCit v6.80 or newer, you can use the simplistic but effective “webcal” protocol to connect calendar clients such as Mozilla Sunbird, Apple iCal, Evolution, etc. Basically, this means you use WebDAV to access and store and ical calendar file.

When you perform a webcal/webdav “publish” operation, any calendar items already existing in the room will be deleted, and replaced with the calendar items you are publishing. Be sure that this is what you want to do. The typical user (or more accurately, the typical client side calendar program) will subscribe to the calendar, edit it locally, and then publish the modified calendar back to the server.

In the above examples, the word “Calendar” is the name of the primary calendar room for your Citadel account. That's the room you can access via the menu on the left, when you login as a user to your citadel groupware.

Depending on the application you are using, a dialogue should pop up and ask your for your login credentials.

You may replace that with the name of any other calendar room to which you have access, for the same effect.
For example, if you have a room called “Meetings” on the “Main Floor”, you would use this URL:

(This assumes that your client will append the name of the user being queried to this URL.) By the way, Citadel automatically publishes free/busy data based on the contents of your calendar – you don't have to configure your client to do this manually.

You can test wether you use the correct URL easily by entering it into your browser. Simply log in to your webcit instance with your username and then try the url. Your browser should automatically download a calendar file with .ics extension.